Gervais Lake
Ramsey County, MinnesotaEutrophic
Gervais Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Gervais Lake reaches 41 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 235 acres and 3.3 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Ramsey County's 49 graded lakes, Gervais Lake ranks 29 — below the local median, though not at the bottom.
Gervais Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. Muskie are on the species list at Gervais Lake, among the lake's 14 documented fish. The lake lacks a documented public access point, so visitor use is limited. Ice-out has been logged at Gervais Lake more than two dozen times, putting the median around Apr 3 — a useful baseline for tracking climate trends. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-17. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 6.2 ft. Phosphorus level: 38 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.2 ft | D |
| Phosphorus | 38 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 41 ft |
| Surface Area | 235.01 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 39% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Gervais Lake (14-day solunar calendar)
→ Is it safe to eat fish from Gervais Lake? (mercury & PFAS guide)
→ Gervais Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.14 m/yr | 5 |
| Phosphorus | → Stable | -0.55 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (60 observations).
Estimated open water season: 245 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-07 (2024) | 2018-04-30 (2018) |
| Ice-In | 2014-11-15 (2014) | 2001-12-20 (2001) |
Most recent ice-out: 2026-03-29
Location
County Ranking
Ranked #29 of 49 lakes in Ramsey County
Cleaner Lakes Within 30 Miles
Gervais Lake holds Grade C. 4 nearby lakes hold higher grades.
- BMccarron LakeRamsey County · mi · Higher grade (C → B)
- BPhalen LakeRamsey County · mi · Higher grade (C → B)
- CRound LakeRamsey County · mi · Higher overall water quality score
- CTwin LakeRamsey County · mi · Higher overall water quality score
Nearby Lakes in Ramsey County
More Minnesota Lake Rankings
State Parks Near Gervais Lake
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2021-09-07 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 62.00 | 0.14 lb |
| Green Sunfish | 9.61 | 0.06 lb |
| Black Crappie | 9.59 | 0.18 lb |
| Spottail Shiner | 8.71 | — |
| Yellow Perch | 7.41 | 0.13 lb |
| Largemouth Bass | 7.27 | 0.9 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
Green Sunfish
Black Crappie
Yellow Perch
From the 2021-09-07 survey
A targeted survey of nearshore and littoral fish species in Gervais Lake was conducted beginning on September 7th, 2021 by Index of Biological Integrity (IBI) Program Staff. Sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine,…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Gervais Lake. 2 reports on file.
- —Fisheries Lake Survey — GervaisFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — GervaisFish Stocking History · MN DNR LakeFinder
EPA Impairment Status
Gervais Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN62-0007-00 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2024-09-17
Monitoring stations: 1